Although levo-alpha-acetylmethadol (LAAM), a derivative of methadone, has been successfully used as an alternative to methadone maintenance in opioid addicts, its effect on concurrent opioid and cocaine abuse has not been ascertained. Thus, this study proposed to examine the clinical efficacy of low- and high-dose LAAM maintenance on opioid and cocaine use in opioid-dependent cocaine abusers. In addition, since contingency management procedures have demonstrated some success in decreasing cocaine use in cocaine-abusing individuals, this study also proposes to examine the clinical efficacy of the presence or absence of contingency management procedures targeting illicit drug use. One hundred sixty male and female opioid-dependent cocaine abusers will be stratified by sex and randomly assigned to one of four treatment groups according to a 2 x 2 experiment design: low-dose LAAM (99 mg/wk) with adjunct contingency management procedures; low-dose LAAM (99 mg/wk) without adjunct contingency management procedures; high-dose LAAM (330 mg/wk) with adjunct contingency management procedures; and high-dose LAAM (330 mg/wk) without adjunct contingency management procedures. The duration of the study will be 24 weeks, with LAAM being administered on a thrice-weekly (MWF) basis. Subjects are inducted onto LAAM during weeks 1-3 and then maintained on their assigned maintenance dose (99 mg/wk or 330 mg/wk) through week 24. During maintenance, the Friday dose will be 1.3 times greater that the Monday and Wednesday dose. At the conclusion of the study, subjects undergo detoxification from LAAM over a 4 week period. For those in the contingency management procedure groups, each drug-free urine submitted will result in a voucher worth a certain monetary value that increases for consecutively drug-free urines (weeks 1-12) or a CT State lottery ticket worth $1.00 (weeks 13-24). Vouchers can be exchanged for mutually agreed upon goods and services at any time during the study. Subjects not assigned to the contingency management procedure will receive monetary vouchers (weeks 1-12) or lottery tickets (weeks 13- 24) according to a yoked-control schedule (that is, not contingent upon illicit drug abstinence). Outcome measures will include: 1) treatment retention, 2) illicit drug use, 3) self-reported adverse and opioid withdrawal symptoms, and 4) psychosocial functioning. Prognostic factors (i.e., sex, post-traumatic stress disorder, and depression), will also be examined in relation to treatment outcome. These findings will assist in developing more effective strategies in treating individuals with combined cocaine and opioid dependence.